What happens if an animal cannot get sufficient oxygen?

it dies

Explanation:

if an animal (depending on the animal) can not get a sufficient amount of provided oxygen it does due to it not being able to breath.

It will suffocate and die.

Explanation:

If humans were not able to get enough oxygen then would die as well

answer; ///(b) it is composed of four protein chains and four heme groups;

explanation:

b,bacteria convert nitrates

into nitrogen gas.

d,plants and animals take in

and use nitrogen compounds.

e,bacteria break down waste    

products and return nitrogen  

to the soil.

a,bacteria convert atmospheric

nitrogen to ammonia.

c,bacteria convert ammonia

to nitrites and nitrates.